Navigation systems, e.g. GPS based navigation devices, are becoming increasingly popular and provide users with a number of capabilities such as location services on a map, turn-by-turn navigation directions to a user in charge of a vehicle via text or speech or graphical interface and traffic services to reroute users around congestion.
Such navigation systems will commonly use global positioning system (GPS) signals to determine latitude and longitude information for the device's location on Earth. Such navigation systems may be able to provide route options between two points, alternative route options in the event of route congestion or route closures and the location of services on route (e.g. food, fuel etc.).
Navigation systems may take a number of forms such as a dedicated GPS navigation device, a mobile phone with GPS capability or a laptop computer with navigation software.
Users may plan routes using a navigation system either by entering a start and end point or by searching for a location to travel to and allowing the device to determine its current location as the start point. In many instances a user may be presented with multiple route options for their journey and may additionally have the ability to customise the route slightly by selecting different roads either via a direct interaction with the suggested route or by selecting or de-selecting journey options in a settings menu (e.g. a user may choose to avoid roads with tolls or avoid motorways).
Navigation systems however do not provide a user with complete freedom to select their preferred route. Additionally, where a user wishes to undertake a journey that is entirely or partially “off road” then a traditional navigation device will not be able to plot a route or may suggest a circuitous route via a road network when a more direct “off road” option is possible.
It is noted that for convenience reference is made within this document to GPS navigation systems. It is to be acknowledged however that alternative location services may be used, e.g. the GLONASS, Beidou (or Compass) or Galileo satellite navigation systems.
Once a route has been selected the navigation system outputs navigation directions to the user to reach their destination.
In certain circumstances however it may be difficult to follow the navigation directions because the boundary of the selected route is not clear to the user, e.g. because of adverse weather conditions (snow on route, flooding, landslip, thick fog, heavy rain etc.).
The present invention has been devised to mitigate or overcome the above mentioned problems with following route directions.